Autopsy results show that he died from "blunt-force injuries of the head," according to a joint statement Thursday from the D.C. Metropolitan Police Department and Office of the Chief Medical Examiner reported by NBC Washington, but the exact manner of death was undetermined.

Also contributing to his death were "blunt-force injuries of the neck, torso, upper extremities and lower extremities," the statement said.

Russian media originally reported that Lesin, a former government minister, had suffered a heart attack.

Russia’s Ministry of Foreign Affairs said Thursday that it had not been kept informed about the case.

“The Russian embassy in the United States has repeatedly requested through diplomatic channels [updates] concerning the investigation into the death of a Russian citizen,” spokeswoman Maria Zakharova said in a statement.

“The American side did not provide us with any substantial information. We're awaiting explanations and official information from Washington concerning the progress of the investigation.”

She did not comment on Russian media reports that Lesin had been a potential FBI informant.

Police who first investigated the hotel room where Lesin's body was found did not find any damage or evidence indicating foul play, a law enforcement source told Reuters.

Lesin served as Russia’s Minister for Communications and Mass Media between 1999 and 2004, and later went on to run the media holdings of energy giant Gazprom. He also helped to create Kremlin-funded English-language news channel, Russia Today.